Method for improving permeability increasing and production increasing effect of coal mine downhole through hydraulic fracturing

Abstract

The invention discloses a method for improving the permeability increasing and production increasing effect of coal mine downhole through hydraulic fracturing. The method comprises the following stepsthat (1) production increasing containers connected with a hydraulic fracturing pipe are manufactured; (2) a production promoter is loaded; (3) the hydraulic fracturing pipe is connected with the production increasing containers, according to the expected size of the influence range of hydraulic fracturing and the required fracturing initiation point, the connection modes that the multiple production increasing containers are continuously connected in series or the production increasing containers are connected with the hydraulic fracturing pipe at intervals are adopted; and then the hydraulic fracturing pipe and the production increasing containers are pushed into pre-fracturing drilling holes, and the sealing devices are installed at the hole opening positions of the pre-fracturing drilling holes; (4) a hydraulic fracturing pump group is started, and fracturing fluid is injected; and (5) hydraulic fracturing is finished, the hydraulic fracturing pump group is separated from the hydraulic fracturing pipe, and the hydraulic fracturing pipe is connected with a gas extraction pipe for pipe-linking extraction operation. The method for improving the permeability increasing and production increasing effect of coal mine downhole through hydraulic fracturing has the characteristics of safety, high efficiency, small engineering quantity and remarkable effect, and can be widely used inthe field of coal mine downhole gas extraction.

Description

technical field [0001] The invention belongs to the technical field of hydraulic fracturing in coal mines, and in particular relates to a method for improving the effect of hydraulic fracturing in underground coal mines for improving permeability and increasing production. Background technique [0002] As a technical measure to enhance the permeability of underground coal seams, hydraulic fracturing of underground coal mine drilling has the characteristics of large permeability enhancement range, remarkable effect, and can greatly improve the extraction efficiency of coal seam gas. Therefore, it has been obtained at present Wider range of applications. However, there are still many problems in the process of hydraulic fracturing, such as: (1) During the process of hydraulic fracturing, a large amount of high-pressure water is injected into the coal seam. The effect of hydraulic fracturing has been affected to a certain extent; (2) Hydraulic fracturing only opens, extends, a...

AI Technical Summary

Problems solved by technology

However, there are still many problems in the process of hydraulic fracturing, such as: (1) During the process of hydraulic fracturing, a large amount of high-pressure water is injected into the coal seam. The effect of hydraulic fracturing has been affected to a certain extent; (2) Hydraulic fracturing only opens, extends, and communicates cracks in the coal seam, and only a small amount of coal dust is discharged from the fracturing borehole in the coal body itself, so the pressure relief effect is not good. Therefore, after hydraulic fracturing is completed, the hydraulic fractures will close in a short period of time, and the effect of pressure relief and permeability enhancement will not be achieved; (3) The direction of hydraulic fractures is mainly affected by the stress and the weak surface of the coal body. Homogeneous and structurally undeveloped areas are mainly affected by stress. Therefore, in the process of hydraulic fracturing, only one main fracture controlled by stress is often formed. Since there is no weak surface around the main fracture, it is difficult to form fracture branches, which makes the hydraulic fracture The range of coal seams that act cannot be uniformly controlled; (4) In the process of hydraulic fracturing, only a small amount of pulverized coal is discharged out of the hole, and hydraulic fracturing itself is a process of injecting pressure into the coal seam, since only a small amount of pulverized coal is discharged And the impact of crack-free branches will cause a certain degree of stress concentration in the coal seam, which will have a certain impact on the safety of coal mine production

Images